You wait decades for a movie that properly tells the story of how AIDS ravaged America — and then three come along at once. It’s director Jean-Marc Vallée’s good fortune that his new film, Dallas Buyers Club, gets there first. We have to wait until early spring to see Chris Mason Johnson’s award-winning Test, set in San Francisco in 1985, and Ryan Murphy’s all-star adaptation of Larry Kramer’s Tony-winning play The Normal Heart. All three projects take audiences back in time to the worst years of the epidemic, but Dallas Buyers Club, which endured an epic and complicated journey from page to screen, may be the most startling of all, with a homophobic redneck as its unconventional hero.

In a mesmerizing performance as the real-life Ron Woodroof, Matthew McConaughey stars as a womanizing junkie who becomes radicalized by an AIDS diagnosis in 1986. Told he has 30 days to live, Woodroof refuses to go quietly into the night, quickly establishing a black market in experimental drugs shipped across the border from Mexico. Jared Leto plays his unlikely sidekick, Rayon, a transgender addict and AIDS patient who partners with Woodroof to provide the drugs to a clamoring base of desperate customers. As with Oskar Schindler, the German industrialist who became an unlikely savior of Jews in Nazi-occupied Europe, the motivation is not entirely pure — there are profits to be made — but the consequences are profound. Woodroof himself lived another six years, and the film suggests that many others survived at least as long, if not longer, as a result of his drug-running exploits.

If Dallas Buyers Club is a little vague on exactly what Woodroof was importing, its David vs. Goliath subtext — like last year’s Oscar-nominated documentary How to Survive a Plague — is a master class in self-empowerment and community-building. Woodroof’s relationship with Rayon is by turns cynical, antagonistic, and, finally, tender and devoted. That the movie avoids sentimentality is a plus.

A lot has been written about McConaughey’s astonishing weight loss for the role, but for Leto, playing Rayon demanded not just shedding weight — he says he stopped counting when he dropped to 112 pounds — but imagining life as a transgender HIV-positive woman in 1980s Dallas. To get there, Leto lived as Rayon on-set and off. “I chose to stay in character the entire time, because there was too much to lose by turning it off after every take,” he says. With his eyebrows waxed and his body skeletal, he’d run routine errands and clock the reactions he was getting. He recalls three, alone, from a trip to Whole Foods: “One was, ‘Wait a second, is that Jared?’ And then, ‘No, it can’t be.’ The second look was, ‘What is that?’ And the third was, ‘I don’t like that.’ That last look was really powerful — to feel that hatred, that confusion, that repulsion,” he says. “Of course I was able to look at it in a clinical way, with all the safety that provides. I couldn’t imagine having to deal with that all the time, and how hurtful that would be.”

The experience, not just in Whole Foods but throughout filming, was instructive for Leto, who scored the part after testing for the role in full drag. What is striking about his performance is the subtlety and serenity he brings to the role, which is a composite of several real-life people; there are none of the stereotypical theatrics we’ve come to expect when Hollywood tackles transgender characters. “I remember sending advance word, saying, ‘Listen, this is great, I want to do this, but I want to make sure that everyone’s OK with me playing this part as a person who is choosing to live as a woman, and not as a cross-dresser,’ ” he recalls. “I think there are a lot of people who don’t know the difference.”

Playing characters in extremis is nothing new to Leto, who won critical raves as heroin addict Harry Goldfarb in Darren Aronofsky’s Requiem for a Dream. And his comeback vehicle — after a six-year hiatus to develop his music career with the band Thirty Seconds to Mars — suggests the absence has only sharpened his ambitions. “It’s kind of like what Sir Edmund Hillary said when they asked him, ‘Why climb Everest?’ and he replied, ‘Because it’s there,’ ” says Leto. “I feel that way about these roles. The greater the challenge, the deeper the reward. I’m really feeling like I’m the luckiest person on the planet right now.”